The present invention relates to an internal combustion engine and, in particular, to an improved internal combustion engine having shuttles whose combined rotational and reciprocating motion produce output power and, at the same time, provide valving for the engine.
There are numerous types of internal combustion engines. Most internal combustion engines have a reciprocating piston wherein the piston slides back and forth in a cylinder and transmits power through, for example, a connecting rod and crank to a drive shaft. This arrangement is called a slider-crank mechanism. These engines are typically two-stroke or four-stroke engines and include valve ports and valves for controlling the intake of fuel and the exhaust of combustion products. The intake and exhaust valves are normally controlled by a rocker arm attached to a push rod that is controlled by a camshaft. The pistons are normally connected to a crankshaft by a connecting rod which allows the piston to reciprocate within the cylinder.
Although the above-described internal combustion engines are widely used, there are disadvantages to using them, such as the number of parts employed and the cost of manufacturing these various parts. Another problem is the need to time the camshaft and crankshaft so that they operate in the correct sequences. Still a further problem is in the balancing of these engines to limit the vibrations which occur in the operation of the engine. An additional problem is variations in output torque on the drive shaft due to reciprocating masses. These variations in output torque are called inertia torques.
Another type of engine is the sleeve valve engine. It is a conventional slider-crank mechanism type of engine with a variation in valving. As described in The Motor Vehicle, K. Norton, W. Steeds, T. K. Garrett (1989), the sleeve valve engine employs a sleeve interposed between the cylinder wall and the piston. The sleeve is in continuous motion and admits and exhausts the gases by virtue of the periodic coincidence of ports cut in the sleeve with ports formed through the main cylinder casting and communicating with the induction and exhaust systems.
As further described in the above publication, the Butt McCullum single sleeve valve has both rotational and axial movement. In the disclosure, the sleeve obtains its rotational and axial movement through a ball and socket joint operated by short transverse shafts. The ball is mounted on a small crank pin integral with a cross-shaft, which is driven at half-engine speed through skew gears from a longitudinal shaft.
The sleeve valve engine has advantages over the above-described reciprocating piston engine. One advantage is that the sleeve valve eliminates the need for poppet valves. Further, it is relatively quiet in operation. A major disadvantage is serious mechanical trouble in the event of piston seizure, which dangerously overloads the sleeve driving gear. A further disadvantage is the cost of the sleeve drive gearing.
Along with the slider-crank type of engines, there are unconventional configurations which have not met with long-term success. One class of these configurations is the Barrel or Revolver engines as discussed in The Internal Combustion Engine in Theory and Practice, Volume 2, "Combustion, Fuels, Material, Design," Charles Fayette Taylor (MIT press 1985). These engines have their cylinders arranged parallel to and generally around the output shaft. In addition, they employ a cam or wobble plate to convert the reciprocating motion of the pistons to rotational motion of the output shaft. The disadvantage to these engines is the reliability of the cam to piston interface. The bearings at the cam to piston interface are in motion, and beefing up the bearings adds mass and creates larger inertia forces which must, in turn, be carried by still larger bearings. Forces are very high at large piston speeds, which makes the engine unreliable. Another disadvantage to these engines is that their arrangement of cylinders makes it difficult to service.
Another class of engines described in the above publication, are the rotary displacement engines. In these engines, a rotating member varies the working volume of the combustion chamber in a way similar to vane-type compressors. The most famous of this type of engine is the Wankel engine. These engines have low vibration. The disadvantage to these engines is that they invariably have combustion chamber sealing problems.
Another class of engines described in the above publication, are those involving cams, levers, or Scotch Yokes, introduced between the piston and the output shaft. These again have large bearings moving in reciprocation. The Fairchild Caminez radial engine came close to success but because of large output shaft torques due to the reciprocating masses (inertia torques) it did not achieve success.